To ask Her Majesty's Government, further to the Written Answer by Baroness Verma on 30 October (WA 114-5) stating that global temperatures have risen less than 1 degree celsius since 1880, on what basis they assert that there has been a long-term upward trend in average global temperatures. [HL3048]

To ask Her Majesty's Government, further to the Written Answer by Baroness Verma on 30 October (WA 114-5) stating that there has been no significant global warming since around 1998, and deeming that period as a shorter timescale, how many years of non-warming they consider would constitute a long-term trend.[HL3049]

To ask Her Majesty's Government, further to the Written Answer by Baroness Verma on 30 October (WA 114-5), whether they consider a rise in global temperature of 0.8 degrees celsius since 1880 to be significant.[HL3050]

The Parliamentary Under-Secretary of State, Department of Energy and Climate Change (Baroness Verma): The assessment that there has been a long-term upward trend in global average near-surface temperatures since the late 19th century is based upon three global temperature records, compiled from observations, by groups in the US and UK. The rate of global temperature rise on different timescales is summarised in table 1 below. The underlying trend over the period from 1880 to 2011 is 0.062 celsius per decade, giving a total change of 0.81 celsius. Such a rate of change has been judged by major scientific assessments to be large and rapid when compared with temperature changes on millennial timescales.

Over this period some parts of the world have warmed at a much faster rate. The land surface average temperature has risen by about 1.1°C and Arctic temperatures have increased by almost twice the global average rate. The consequences of this warming are already seen across the globe. For example, northern hemisphere sea-ice and snow cover have decreased markedly, most glaciers have retreated and the risks of certain extreme weather events occurring have increased.

8 Nov 2012 : Column WA225

Statistical (linear trend) analysis of the HadCRUT4 global near surface temperature dataset compiled by the Met Office and Climatic Research Unit (table 1) shows that the temperature rise since about 1880 is statistically significant.

Time period

Linear trend (°C/decade)

Absolute change in temperature described by linear trend (°C)

1880-2011

0.062±0.009

0.81±0.13

1900-2011

0.074±0.011

0.82±0.13

1950-2011

0.106±0.025

0.66±0.16

1970-2011

0.166 ± 0.038

0.70 ± 0.16

Table 1. Trends fitted to monthly global temperature anomalies for HadCRUT4, with uncertainties describing 95% confidence interval bounds for the combination of measurement, sampling and bias uncertainty and uncertainty in the linear trend fitted to the data. The statistical model used allows for persistence in departures using an autoregressive process (ie that an individual value is not independent of the previous one).

Statistical analyses and modelling of the global temperature record have shown that, because of natural variability in the climate system, a steady warming should not be expected to follow the relatively smooth rise in greenhouse gas concentrations. Over periods of a decade or more, large variations from the average trend are evident in the temperature record and so there is no hard and fast rule as to what minimum period would be appropriate for determining a long-term trend.

In the comments, Shub notes that the statisticians at DECC (who are presumably advising Verma) are using the IPCC's "new" calculus. Paul Matthews pointed out some years that this is illegitimate and entirely bogus.

Anyway, without knowing what the other columns would look like for those periods, there's Lindzen's very basic point that an increase of 0.8degC is no cause for alarm. And without assumptions about the effect of aerosols the models would surely say the same - assumptions Nic Lewis is finding are increasingly called into question by real world data. Less and less place to go - except I suppose for an immeasurably small delta in the temperature of the deep ocean.

Meanwhile, thanks to the Bish for the tweet this morning that led to this excellent point from Tory MP Douglas Carswell:

Nothing will be more toxic to the Tory brand than the idea that we are the party of corporatist fat cats and rent seekers. We need to give serious thought to the free market alternatives to avoid this.

Either She's been trawling realclimate or has commissioned the work of a much overpaid manderin. In all of this argument it strikes me that warmists believe that the temperature started to rise following the building of the first smokestack at the very beginning of the industrial revolution. After, say, ten years as hundreds more were built they are suggesting that from that point as carbon dioxide levels started to rise there was a discernible and measurable increase in global temperatures.This is absolute nonsense of course.One would have expected carbon dioxide levels to have increased lby a factor of hundreds if logic were applied to this thinking considering the amount of carbon being burned over the past 100 years but levels are low comparatively.It would be interesting to ask these climate scientists at what point can they see a rise in carbon dioxide levels and a rise in global temperatures. I'll bet they'll have a hard time trying.

Should be easy to find out who said 10 years were enough before 15 years were enough before 16 years were enough before there was no hard and fast rule to find out how many years are enough thereby saying all statistics is bunk.

There’s a statistically significant difference between the height of members of the House of Lords in 2013 and that of their predecessors in 1880, with a long term trend which is not only significant on millenial timescales, but which, if extended backwards, proves that Magna Carta was signed by hobbits. Whether anything should be done about it is another question.Lord Donoughue asked the wrong question. It’s not surprising that he got the wrong answer.

It would have been a bit better if Donoughue had asked about statistical significance rather than significance, although even then I'm not sure where this gets us.

In my view the amount of energy devoted to the idea that 'warming has stopped' is misguided, for a number of reasons.

The most basic is that many skeptics tend to confuse lack of statistically significantwarming with lack of warming. But that's a fundamental error.

Looked at in statistical terms we are asking whether the data in a given period can reject a null hypothesis.

Skeptics usually chose the null hypothesis is that temperatures are explained by random variation around a constant level. For various models of random variation (e.g. autocorrelation, normal distribution, etc) that hypothesis cannot be rejected at the 5% level taking data since 1998. Because this null hypotheses cannot be rejected, goes the argument, 'warming has stopped'.

Two problems.

First, you can reject it by just by taking a lower confidence level or, crucially, more years. There is a trade off between number of years and p value. If you accept a worse p value, use fewer years. If you want a better p value you can get it just by using more years.

The focus on 1998 as the year that 'warming stopped' is partly because 1998 was an unusually warm year. But it is partly just a result of a statistical rule of thumb, one that Fisher, when he introduced it, made clear should be chosen independently for each application in mind.

Second, we can equally well reject the null hypothesis that 'the trend since 1970 stopped and fell to zero in 1998'. Lack of statistically significant warming is not the same as statistically significant lack of warming. All the p value on the trend is saying is that to answer a useful question we need a better analysis or more data.

I don't usually come over Popperian, but many skeptics seem to be fans so they should know that failure is to reject the null hypothesis is not the same a accepting the null hypothesis.

I'll stop there for now, but I think that the deeper you look at it the more misguided it becomes. I do think that the relatively slow warming in the last 15 years point more toward luke- than runaway-warming. But I don't think it has yet established warming has deviated from the rate since the 1970s in physically significant way for thinking about projections up to the next century or so.

And on what basis do we 'know' what the temperature was in Congo, Zimbabwe, Brazil, Peru and countless other places in 1880? We might have an approximate, very approximate idea. From such crude notions how can we say, even side-stepping the question of whether it matters, that temperaure has increased by precisely 0.8C since then? The concept of global temperature, before the satellite era, is a fiction, and to base policy on fiction is folly. We would do better to sit tight and wait until we've got a meaningful period - 100 years or so - of satellite records before we decide whether temperature is rising and if any policy responses are needed.

JKI agree with you, but at what point do you look at the pattern of temperature over, say, the last 150 years (or starting from whenever you believe records were reliable enough to make sense) and conclude that in line with that pattern temperatures look as if they have peaked and will be heading down again for the next 30 years or so?The warmist argument, which as we all know is based on models which have certain of the built-in — albeit we hope unconscious — bias of their programmers, is that whatever upward trend you establish that trend is going to continue forever. At least more or less.Whereas there is, as yet, no evidence that recent warming is outwith the bounds of normal variation which suggests that at the very least we ought all to be preparing for the possibility that we are about to head into the downslope of that 30-year cycle or even, given the state of the sun, a deeper fall than that.

'so there is no hard and fast rule as to what minimum period would be appropriate for determining a long-term trend.'

Expect where it such a time scale is used to prove AGW that is .But in effect their saying that the AGW theory can never be falsified by data , which ironically means its not science in the first place.

Your comment about Douglas Carswell at 8.35am, I wonder if you've read his book "The End of Politics" which struck me as one of the most honest and personally courageous books about politics I have read. (He admits, in effect, that there is very little politicians can do against quangos and the rest.)

"there is no hard and fast rule as to what minimum period would be appropriate for determining a long-term trend"Thank you, thank you, thank you. So most formulations of anthropogenic global warming are not falsifiable and are therefore not science.

quoteIt would be interesting to ask these climate scientists at what point can they see a rise in carbon dioxide levels and a rise in global temperatures. I'll bet they'll have a hard time trying.unquote

The... no, make that one... previous position was that the CO2 signal should show above natural variation some time in the early 70s. Now, no doubt, that date has been moved as it won't match some other part of the rapidly evolving consensus around the settled science. By being polite and persistent I managed to get tamino to calculate the relative CO2 forcings during the two twentieth century warming periods. .25 w/m^2 compared to 2 w/m^2. So one can't even distinguish when CO2 warming kicked in.

The human isotope signal is even worse: if you look at Ferdinand Engelbeen's graphs you'll see that the heavy C depletion does not begin in 1850ish, as often cited, but 70 to 80 years before that.JF

The recent lack of warming is important only in the context of the degree to which CO2 affects temperature, and sceptics, and indeed anyone with scientific curiosity, should by asking exactly what mechanism is in play that holds temperatures more or less steady in the face of a rise of some 32ppm, around 8%, of CO2 in the atmosphere. Unless we know what is causing the temperatures to stay steady in the face of rising CO2 levels then a "very likely" that CO2 caused most of the warming at the end of the 20th century, on which all our climate change policies are based looks, is, to use a scientific term, "flaky".

There is a very interesting thread on Climate Etc. about fooling ourselves, I think you may well have fallen into the trap of putting your own beliefs into the mouths of others and then destroying their position. Or am I fooling myself.

I agree that a discussion about physics and feedbacks is ultimately more important. But there is a particular discussion about 'no warming since 1998' that I think most people following the climate discussion will recognize.

Although there are variations I think that in this specific debate the controversy is over whether there has been a recent trend in global atmospheric temperatures. In this specific debate about 'statistically significant warming' I think I am correct in identifying the common, albeit implicit, skeptic hypothesis.

This specific debate is about the fit of temperatures to a statistical model. The neglect of underlying physics is indeed another reason that I think it gets too much attention.

To ask Her Majesty's Government, further to the Written Answer by Baroness Verma on 8 Nov 2012 : (WA225) stating that the temperature trend rise of about 0.8C since about 1880 is statistically significant, whether this rise is attributed primarily to human activity and, if not, on what grounds the slower trend rise of about 0.7C since about 1970 is being thus attributed.

To ask Her Majesty's Government, further to the Written Answer by Baroness Verma on 8 Nov 2012 : (WA225) stating that there was 'no hard and fast rule as to what minimum period would be appropriate for determining a long-term trend', why they are content to consider the period 1970-2011 as constituting one.

To ask Her Majesty's Government, further to the Written Answer by Baroness Verma on 8 Nov 2012 : (WA225) stating that 'Statistical analyses and modelling of the global temperature record have shown that, because of natural variability in the climate system, a steady warming should not be expected to follow the relatively smooth rise in greenhouse gas concentrations...', and noting that the late Professor Karl Popper has remarked that for a hypothesis to be considered a scientific assertion it must be capable of being falsified by experimental data, what conceivable experimental findings might be accepted as falsifying the AGW hypothesis?

"noting that the late Professor Karl Popper has remarked that for a hypothesis to be considered a scientific assertion it must be capable of being falsified by experimental data, what conceivable experimental findings might be accepted as falsifying the AGW hypothesis?"

Obviously if you don't specify what exactly the "AGW hypothesis" is supposed to be then it cannot be falsified.

In fact I don't think that either Popper or reducing climate science to one narrow hypothesis are particularly useful, but here goes:

"Most of the warming observed over the last 50 years is attributable to human activities" would seem to me to be as testable as most scientific statements in historical sciences such as geology and astronomy where we try to explain similar "one off" events.

"Climate sensitivity is x degrees" would seem to be testable, to a first approximation, by doubling CO2 and waiting a century or two? If don't have the data for a decisive test now, Popper only says that an observation should be doable, not that it has to be quick or easy let alone already done. In fact it's much better if it has not been done before the theory is proposed.

"Although there are variations I think that in this specific debate the controversy is over whether there has been a recent trend in global atmospheric temperatures. In this specific debate about 'statistically significant warming' I think I am correct in identifying the common, albeit implicit, skeptic hypothesis."

I don't believe there's a debate about whether there has been a trend in recent global atmospheric temperatures, everyone, alarmist or sceptic, can see that the trend upwards has stopped. The sceptics don't have a hypothesis they don't need one. The alarmists have a hypothesis that CO2 causes warming which will lead to catasrophic climatic events. In the event that the first part of the hypothesis proves to be questionably because of a hiatus in warming for 16 years ( don't care whether it's statistically significant, the rate of warming has dropped dramatically and one of the pillars of the alarmist hypothesis was that the late 20th century warming was at an unprecedented speed and the hiatus kicks that pillar from underneath the hypothesis).

You seem to be implying that it's impolite for sceptics to bring up the question of the observations aren't matching the hypothesis. The nub of them raising this hiatus is "uncertainty", remember it wasn't so long ago that the scientists (risibly) were telling us "the science was settled", now the hypothesis cannot explain the hiatus, so it, to me at least, seems extremely Popperian to go back to the scientists who in 2007 told us with 90-100% certainty that CO2 caused the late 20th century warming and ask them to explain why the continued rise in CO2 hasn't resulted in a concomitant rise in temperature.

The hand waving about not expecting the rise to be a continuum, should be explained scientifically. What it is that has caused the hiatus in temperature rise. If they cannot explain that then they for sure cannot say with 90-100% certainty that the late 20th century temperature rise was caused by human emissions.

In short if there are unknowns causing the cooling that has kept the temperature steady, why should there not be unknowns ( or more likely given the parlous state of climate science at the moment, "ignoreds") that caused the warming.

Keep in mind people are trying to change our whole way of life. A way of life that has seen huge steps in medicine, in communications, in general well being in the Western Industrialised Societies. A way of life unprecedentedly comfortable for most human beings, that enables us to put huge amounts of money into science and the arts, unprecented in history. A way of life that enables us to be concerned about the plight of other human beings in other parts of the world and try to help them. A way of life that enables people to spend their time in parasitic activities, like trying to change our way of life and their tool for doing this is the threat of catastrophic global warming. If you were to ask me we should be scrutinising every aspect of the hypothesis and challenging every missed forecast and wrong observation in the greatest detail because if we don't we will continue on the journey of the biggest hubristic folly in human history, our attempt to control the climate.

"..Obviously if you don't specify what exactly the "AGW hypothesis" is supposed to be then it cannot be falsified..."

Indeed - I simply wrote this as a shorthand for the much more precise wording that would have gone into the real Parliamentary Question, and which would have taken me several hours to compose properly.

The point I make is that PQs are a kind of tennis game, and the government have left themselves open here. Let us assume that the response is as you suggest - that a century or two is needed to 'disprove the hypothesis'. That obviously will result in the following point being made:

"My noble lords, are we to accept that a multi-billion pound spend which will severely deplete our economy now must be made on a simple guess that there might be a problem - a guess which has no chance of being validated within our lifetimes or, indeed, that of our childrens?..."

In the Parliamentary reply it was stated that [t]he underlying trend over the period from 1880 to 2011 is 0.062 celsius per decade, giving a total change of 0.81 celsius. Such a rate of change has been judged by major scientific assessments to be large and rapid when compared with temperature changes on millennial timescales.

Do we really know how fast the warming was during the build up to the peaks reached in the Roman and in the Medieval Warm Periods? If we do not know, then how is it possible to asset that the recent warming is "large and rapid when compared with temperature changes on millennial timescales"? If we do know how fast warming was then, can anyone supply the figures comparing the 20th century rate of warming with the rates in the Roman and Medieval periods?

You beat me to it ^.^Had thermometers been invented at around 1000AD then a couple of centuries later some might have been asking what the L was going on? However no thermometers so no worries.Today I hope that all present are agreed that The Hockey Stick was indeed an illusion and that the good old Medieval Warm Period was at least as warm as today. Like Geronimo (brilliant post!) I am not interested in statistical significance, I am interested in what is happening, why is it happening and is it unusual?We know that our scientists think the planet warmed in the 20th century but we know that such warming has happened before.We know that it has stopped warming and that our scientists do not understand why?It is also worth mentioning that after the recent events at the Met Office; anyone mentioning 95% probabilities around here is not likely to receive a friendly reception.

Actually folks, the situation could be summarised like this:'We, Her Majesty's government, have taken a stance on this issue and wil come up with statistics, trends, models, and dodgy historical data to support it till the cows come home - in the same way as Her Majesty's government in Victorian times decided that typhoid was due to 'miasma' (bad air) and nothing to do with contaminated drinking water; and in the same way that as part of Her Majesty's government's drive as part of 'carbon reduction' that you would all buy stupid wound-up fluorescent light bulbs which will create a nice problem of mercury in drinking water as all the spent bulbs finish up in landfill rather than wait for LEDs to be developed which last 25 years and consume a quarter of the power of stupid 'low energy' lamps...''So there...!'Happy New Year....

DennisA, I think it's likely that these answers more directly originate in the CCC. They certainly read like that. Either way, the Baroness is at fault for not questioning her sources more carefully. But then again her business and parliamentary background probably doesn't help her very much.

HMG are using "post-normal" IPCC calculus ! The slope of a curve is no longer dy/dx. In this upside down world of "climate science" the slope has been redefined as (Yend - Ystart)/(Xend - Xstart). Mind you Pachauri is trained as a railway engineer !

This will anyway come back to bite them as the latest data show "decelerating" global warming. see here

Paul Matthews pointed out some years that this is illegitimate and entirely bogus.

And I had a blazing row with BBD about this. I couldn't make him understand that it was quite wrong to compare part of a time sequence (the latest warming part) with the whole sequence which included both warming and cooling.Now I understand! In keeping with his usual level of comprehension he had simply regurgitated this piece of claptrap without understanding it.I'm glad to have it confirmed that I wasn't being quite as dense as I was beginning to think I was!

Listening to Radio 4 this morning about rising food prices the focus is already off Global Warming and on to extreme weather. Climate Change causes localised floods _and_ droughts apparently. The message "Global warming? What Global Warming?...Look over here at the starving kiddies, that's all your fault and you need to pay more taxes to feed them" is already being punted.

The sad fact is the ecowarriors will find scientists who will back up these assertions in return for grants to find the cause and the cure.

I remember a certain looney left comedian in the UK shouting "it's just weather idiots" when someone pointed out there was unseasonal snow in southern UK in November...well guess what Marcus..."it's just weather when when it is localised too."

Found an interesting bit in Paul's website. Apparently, the IPCC 'global warming-is-accelerating' graph was inserted, in typical IPCC fashion, after the second round of review but before the final version. The material was subject to review by governments and the Chinese government objected to the graph being included. From Paul's page (emphasis mine):

The Chinese Government suggested deleting this, pointing out that 'These two linear rates should not compare with each other because the time scales are not the same'. Well done to the Chinese Government for spotting that.

Your pithy and cogent summary, with a little tidying, should be required reading for all those UK govt. types who endlessly repeat the mantra of CO2, global warming, extreme 'weather' events, need for urgent action, etc.

And at the end, a simple request should be asked: to wit, please respond equally cogently to these points.

What is deeply depressing of course, given that it is the Whitehall machine that will be lumbering into action, is that any answer will be no more than a smug, ignorant and irrelevant re-cycling of 'Baroness' Verma's original answer.

It will take a great deal more than simple truth to deflect this particular behmoth.

"It will take a great deal more than simple truth to deflect this particular behmoth."

I fear all the cogent explanations in the world will do nothing, what is needed is for politicians who support this nonsense are put in fear of being kicked out of office/not winning office. Look at Miliband Minor grovelling on the Labour Party's immigration policy. They want power at any cost and will adopt any policy that they think will give them power, not Dave's new doubts about the EU. For the moment at least, we, the people, are the masters, but the people, like the politicians, and indeed myself on many issues, rely upon expert advise to form their opinions. On climate we've had an almost complete MSM blackout of views challenging the IPCC. (Actually, I've always made clear that there are lots of climate scientists doing a good job trying to get better insights into our climate system who make great contributions to WG1 and WG2, but we have two problems, the lead authors and authors seem to be activist scientists, who to be fair are still humble in their conclustions, but the SPM is written by politicos, and read by hacks, amplified and transmitted to the people. That's not going to end anytime soon).

The alarmist have done a remarkable job in making those who challenge the SPMs as cranks. Roll on the time when the great British public have had enough. Of course, the environmentalists are equally aware of the dangers, for them, of the public, who have never voted for them, realising the intentional damage they, the environmentalists, are doing to our societies, so have tried, multiple times to take the decisions out of the hands of the people by moving the management to international bodies who can operate without the irksome need to be told what to do by the people.

I have been around for 70 years or so, and all of my working-years during that time were spent in the great outdoors. I can say without any doubt that the weather is no more 'iffy' now than it has ever been during that period. Indeed, it is clear to me, having experienced many of them, that most of the greatest periods, or instances of extreme weather happened some time before the present decades. Floods, droughts, or periods of extreme warm or cold are probably less frequent or noticable now than they have been in my earlier lifetime. But certainly the alarmism in reporting such events has increased, and at an alarming rate!

The earth has been cooling for 10,000 years but temps will rise and fall even though the line is heading downwards. The temps for the last century were well within the plus/minus 1.5C for average temperature change expected per century. In geological history even 10,000 years ago is a very short timescale. That Her Majesty's Government finds the last decade or so having any relevance tells one more about their ignorance than their knowledge.To point out that this particular Holocene is cooler than most of the previous ones would be something beyond their comprehension.

As has easily been demonstrated by many (eg Lucia @ the blackboard), recent (last few years) temp data of the major global indicies are now falling outside the IPCC 5-95% confidence range of projected temperatures, yet they are still using the same models for both projection and attribution studies. While I am fine with using the same models for the projections, surely attribution must be called into question if "noise" (IOW, "unforced variability") is greater then previously believed. Yet this does not appear to be the case in any "official" report that has been released, and would appear to be on the path to being buried in footnotes and apendicies for AR5 (and even then, more as a CYA effort than any attempt to convey the nuances of the real data). Perhaps the young and experienced - as well as the gullible - will accept this, but I am afraid that most people, when they find out, will be more than a little annoyed, especially those of us who have been lumbered with ridiculous renewable energy subsidies and carbon taxes. The damage this will do (if any) to science in general and climate science in particular is yet to be determined, but is of more concern to me than any political fall-out from same.

It's worse than we thought. If you examine the isotope data carefully, you will find that the variations in the heavy isotope do NOT follow human emissions, but rather natural variations in overall CO2 level, which suggests quite strongly that the changes in isotope ratio are NOT related to human emissions, but instead are related to variations in the natural sources and sinks of the various isotopes. Together with the fact that it appears that sinks have managed to "disappear" approximately half of all human emissions in both 1960 and 2000( and all the years between and since, for that matter), it becomes increasingly difficult to credit that human emissions are a significant driver of atmospheric CO2 levels, regardless of whether or not CO2 is a significant driver of climate.

I read every day, I don't comment because I don't think I am informed enough compared to other posters. I am often confronted by "alarmist" friends and without going into scientific questions I always ask them the same few questions when they state that "the world is warming because "x" of the warmest years since 1880 have been in the last few years".Q How old are you and how tall are you?A (Say) 62 and 6ftQ how tall were you when 20 yrs old?A 6 ftQ So 42 of your "tallest" years were in the last 42 years. Have you grown every year?A Errrrr No

The world has warmed by 0.8 deg since 1880. This is apparently "catastrophic". So let's confirm those figures. (Feel free to use your smartphone, computer or any other device to find the temp, the location of temp reading and the person who recorded the temp reliably for over 30 years) Q In 1880 what was the temp ata. The North Pole?c. The South pole?d. In the capital city, or any other location in the following countries/states - Brazil, Mali, China, Korea, Easter Island, Kazachstan, Oklahoma, Northern Territories Australia etc etc ( I could go on for ever)A ErrrrSo if you can't supply any reliable temp recordings for 1880 how do you know the "global temp" in 1880?A ErrrrrrQ And if you don't know the "global temp" for 1880 how do you know how much it has risen/fallen/changed fallen since 1880A Errrr

Well, not very sophisticated, but then most "warmists" are also not very sophisticated.Much appreciate the work done by you all, and all the very sophisticated posts on this site. I will continue to read and learn - but maybe not contribute much! Just wish our "leaders" would read and learn as much!! Thanks BHP